1. Technical Field
The present invention relates to a fuel injection method of an internal combustion engine and in particularly to a fuel injection method of an internal combustion engine in which an atomization of a fuel spray injected from a fuel injector is heightened and the fuel spray is supplied to an intake manifold, and a fuel injection apparatus of an internal combustion engine and in particularly to a fuel injection apparatus of an internal combustion engine in which an atomization of a fuel spray injected from a fuel injector is heightened and the fuel spray is supplied to an intake manifold.
2. Prior Art
Recently, from an aspect of an environment protection, exhaust gas regulations and fuel consumption regulations in the automobile field have been enforced exclusively from year to year. As a result of these requirements, improvements in an exhaust gas purification and the fuel consumption of an internal combustion engine and various kinds of internal combustion engines (such as a lean burn engine and a direct injection engine etc.) have been proposed.
In the above stated direct injection engine, there is a problem from a manufacturing cost in accordance with many alternations about an engine base, and it has needed to provide a piston head which has a specific shape configuration and requires some surrounding devices. As a result, there is continued desire for an improvement of combustion in an internal combustion engine using the above stated lean burn engine.
The above stated lean burn engine is an engine in which an air-fuel mixture is performed to lean and burn by employing a fuel injection system in which a multi point injection (MPI) system for carrying out a fuel injection from a fuel injector which is provided on a respective cylinders. The fuel injection is synchronized to an intake stroke so that a lean characteristic of the air-fuel mixture is performed.
On the other hand, by gathering a rich air-fuel mixture in which a spark is enabled to carry out at a surrounding portion of an ignition plug, an improvement of the fuel consumption can be attained in the internal combustion engine and an improvement of an exhaust gas purification can be attained in the internal combustion engine. As to the techniques relating to the improvements of the lean burn engine, such techniques are shown in Japanese application patent laid-open publication Hei 8-177,689 and Japanese application patent laid-open publication Hei 11-159,424.
In the above stated prior arts, in light of the adhesion of the injection fuel to an intake port, and the cylinder etc. of the engine, this adhesion invites an aggravation of the exhaust gas purification. In other words, to dissolve a fuel wet characteristic, an atomization of particle diameters (grain diameter or grain sizes), such as 80-100 xcexcm, of the injection fuel and further an advance arrangement structure of an injection hole portion of the fuel injector (the injection hole portion of the fuel injector is near the intake port) are carried out. The fuel consumption in the internal combustion engine and the improvement of the exhaust gas performance in the internal combustion engine are thereby attained.
In accordance with the advance arrangement structure of the injection hole portion of the fuel injector, by carrying out the atomization of the particle diameters in the above stated injection fuel, however the aggravation of the exhaust gas performance in the internal combustion engine according to the adhesion of the injection fuel to the cylinder etc. may be dissolved.
However, since the kinetic energy of the above stated atomized injection fuel is smaller than the kinetic energy of the injection fuel having the ordinary particle diameters, there is a problem of a delay in time of the injection, fuel in which a penetrating force of the fuel injection is made small and a time is delayed for the injection fuel to reach the cylinder from the fuel injection apparatus (i.e., the fuel injector). Because of the delay in time of the injection fuel, there is a problem in which all of the injection fuel can not enter in a combustion chamber of the engine during an intake stroke time. In other words, the delay in time of the injection fuel of the fuel injector to the combustion chamber of the engine is a transportation delay.
Herein, the inventors of the present invention have determined that the delay in time of the injection fuel (all of the fuel can not be entered in the combustion chamber of the engine during the intake stroke time) makes it difficult for the injection to be synchronized to the intake stroke time in the fuel injection system in which the MPI (multi-point injection) system is performed. As a result, it is necessary to reduce the delay in time of the injection fuel during the intake stroke time.
However, in the above stated prior art, only the fuel wet characteristic can be reduced. There is no particular consideration about the dissolution of the delay in time of the injection fuel during the intake stroke time or the transportation delay of the injection fuel during the intake stroke time.
An object of the present invention is to provide a fuel injection method of an internal combustion engine and a fuel injection apparatus of an internal combustion engine. In such a fuel injection apparatus (i.e., a fuel injector) performed by a MPI (a multi-point injection) system, a quality of an air-fuel mixture in a cylinder and a formation condition of the air-fuel mixture in a cylinder can be improved.
Another object of the present invention is to provide a fuel injection method of an internal combustion engine and a fuel injection apparatus of an internal combustion engine, in a fuel injection apparatus (a fuel injector) which is performed by a MPI (a multi-point injection) system, so that an atomization degree of a fuel spray injected from a fuel injector can be more heightened (i.e., increased) and the fuel spray into an combustion chamber can be more suitably supplied.
A further object of the present invention is to provide a fuel injection method of an internal combustion engine and a fuel injection apparatus of an internal combustion engine. In such a fuel injection apparatus (a fuel injector) performed by a MPI (a multi-point injection) system, an orientation (i.e., a directionality or a directional movement) of a fuel spray to be subjected to the injection of a fuel injector can be suitably adjusted and a shape of the fuel spray can be suitably adjusted.
A further object of the present invention is to provide a fuel injection method of an internal combustion engine and a fuel injection apparatus of an internal combustion engine. In such a fuel injection apparatus (a fuel injector) performed by a MPI (a multi-point injection) system, a delay time of an injection fuel injected from a fuel injector can be lessened.
In a fuel injection apparatus of an internal combustion engine according to the present invention, basically, the fuel injection apparatus of the internal combustion engine comprises an intake valve device for opening and closing an intake port, a fuel injector driven in accordance with a control signal from an engine control device which is arranged in an upstream side of the intake valve device, and an intake air flow control device arranged near an upstream side of the fuel injector. A fuel injection is synchronized with an intake stroke of the internal combustion engine. A fuel spray injected from the fuel injector is generated to orient to an inner wall face which is an opposed side of an inner wall face of a cylinder head of a side of the fuel injection. When the intake valve device is opened, an intake air flow having a strong fluidization, which flows in from the intake air control device, transports the fuel spray.
In the fuel injection apparatus of the internal combustion engine according to the present invention, the fuel injection system in which during the intake stroke a multi-point injection (MPI) system is synchronized and an optimum fuel injection period is established. The mixture of the fuel spray injected from the fuel injection with the intake air flow having the strong fluidization is promoted effectively and the fuel spray is transported to the respective cylinders such that an improvement about the quality of the air-fuel mixture can be obtained. The atomization of the fuel spray can be attained using the fuel upstream swirl type fuel injector. Further, a fuel spray is formed and directed to the intake airflow having the strong fluidization. Further, since the distance between the fuel injection hole of the fuel injector to the intake valve of the respective cylinder is shortened, the lowering of the penetration force, which has been the problem according to the atomization of the fuel spray in the prior art, can be compensated. Further, a reduction in cost can be obtained.
Further, in an embodiment of the fuel injection apparatus of the internal combustion engine according to the present invention, the injection hole axis of the fuel injector is arranged to direct in the dish port of the intake valve. Further, the fuel spray injected from the fuel injector is generated and oriented to the inner wall face, which is the side opposed to the inner wall face of the intake valve in the fuel injector side. Accordingly, as to the fuel spray configuration, in the inner wall face side of the cylinder head in the fuel injector side, the spread angle is small (i.e., the fuel spray amount is small). In the inner wall face side of the opposed side, the spread angle is large (i.e., the fuel spray amount is large). As a result, the adhesion amount of the fuel spray to the inner wall face of the cylinder head can be reduced.
Further, in another embodiment, the injection hole axis of the fuel injector is arranged to direct in the dish port of the intake valve, and further the fuel spray injected from the fuel injector is deflected to the inner wall face side of the side opposed with the inner all face of the cylinder head in the fuel injector side. Also, in the cross-section that is orthogonal to the injection hole axis of the fuel injector, the fuel spray is generated to have the flatness shape (for example, with the two intake valves the fuel spray is substantially concentrated) and when the intake valve is opened, the intake air flow having the strong fluidization which is flown from the intake air flow control apparatus can be transported.
Additionally, since the minute spray injected from the fuel injector is generated flatly and deflective, and when the injection hole axis of the fuel injector is arranged in the dish port of fuel intake valve, the fuel adhesion to the inner wall face of the cylinder head which is made as the problem in an axial symmetric spray can be lessened.
As a result, since this does not require an alteration of the layout for the base engine, a reduction in the cost can be attained. Further, by suiting the flatness degree and the deflection degree in the desirable form of the fuel spray can be selectively in compliance with request, it is possible to obtain the correspondence of the various kinds and comparative, styles in the fuel spray.
Further, according to the compatibility of the atomization of the fuel spray, an air-fuel mixture having good quality can be generated, and an improvement of the exhaust gas purification and the fuel consumption can be attained.